Users capture a variety of images using conventional image capture devices, such as conventional cameras or conventional digital cameras. Often, the user desires different characteristics for different images being captured. Typically, the characteristics depend on the objects within the image in which the user is interested. For example, objects within a portrait image typically include a subject or subjects in the foreground and a variety of other objects in the background. When the user captures a portrait image, the user typically desires the subjects to be in focus, appearing sharply defined in the image. However, the user also typically desires the objects in the background to appear soft, or out of focus. Similarly, when a user captures an image of a moving object, the user typically desires the moving object to be in focus.
In order to allow a user to capture images having the desired qualities, conventional image capture devices, such as conventional cameras or conventional digital cameras, may have conventional hint modes. Conventional hint modes typically set the shutter speed and aperture size based on the conditions under which the image is taken. For example, hint modes may include a conventional portrait hint mode, sport mode, or twilight mode. In conventional sport mode, the shutter speed of the conventional image capture device is set to be very fast. Thus, the moving object may appear in focus. In the conventional twilight mode, the shutter speed is set much lower, to allow sufficient light for image capture. In the conventional portrait mode, the aperture is set to have a medium focus zone, to allow the subject to be in focus and the background soft. The focus zone is the range around the focus distance in which objects will appear sharp and in focus. The focus distance is distance from the image capture device which is most sharply in focus. The focus zone is inversely proportional to the aperture size. In addition, some conventional image capture devices may be set to automatically select a hint mode based on an analysis of the image data which indicates the conditions under which the image is captured.
Although conventional image capture devices allow some improvement in image quality, some images may still not have the desired qualities. This is particularly true of portrait images. Often, the subjects in the foreground of a portrait image are relatively close to other objects that are in the background. As a result, the focus zone encompasses both the subjects in the foreground and the other objects in the background. Both the foreground and the background will be in focus, appearing sharply defined in the portrait image. The portrait image, therefore, has undesirable characteristics and relatively poor quality.
Accordingly, what is needed is a system and method for improving portrait image quality, particularly for images in which objects in the background and objects in the foreground are relatively close. The present invention addresses such a need.